The present invention relates generally to instruments for grasping, gripping or manipulating distant objects and more particularly to endoscopic instruments for performing such operations as part of a medical procedure.
Flexible forceps or other grasping instruments are frequently used in conjunction with flexible endoscopes or other visualization devices for retrieving or otherwise manipulating objects within a patient's body without the need for conventional surgical intervention and the attendant risk and resultant patient recovery. Conventional forceps or graspers of this type frequently include an elongated, tightly-wound spring-coil sheath or body having a “handle” or other such control assembly at a proximal end and a jaw assembly at a distal end, with the distal end being inserted through a body opening either separately or through an endoscope. The control assembly is typically a hand-operated push-pull mechanism that extends and retracts a control wire or thin cable through a longitudinally-extending lumen in the sheath or body. The control wire in such instruments is attached to pivoting thin wire jaws that are spring-biased laterally outwardly to open when they are extended longitudinally outwardly beyond the end of the sheath or body and to close when retracted longitudinally back within the sheath.
As a result, these prior art jaws move longitudinally relative to the instrument's sheath or body and move relative to the object to be grasped or manipulated, during opening and closing. This makes it difficult for the operator to accurately position and open and close the moving jaw assembly around the stationary object, especially in the very close quarters typically encountered in medical endoscopic procedures. These jaws can also thus move into and out of the focal range of the endoscope, thus further complicating the operator's ability to see and accurately maneuver them relative to the object. Furthermore, in order to be able to open wide enough to surround or enclose the object to be manipulated, the jaws in such prior art designs are necessarily inordinately long. Because these long jaws must also be very thin in order to allow the instrument to be inserted through small body openings, their length-to-diameter (L/D) ratio is high, often 100/1 or even higher. Thus the typically resilient jaws, which are laterally unrestrained and unsupported when extended to their open positions, often lack sufficient column strength or stiffness to prevent significant jaw deflection or displacement relative to the object, to prevent undesirable changes in jaw shape or geometry, or to avoid loss of accurate jaw positioning relative to the object. This often results in undue repeated maneuvering of the instrument to get it into proper position, repeated attempts to grasp and hold or otherwise manipulate an object, and the resultant trauma and damage to the surrounding tissue in medical endoscopic procedures.
The present invention seeks to overcome these and other disadvantages by providing an improved controlled-motion instrument for grasping, holding or otherwise manipulating an object in operations such as those performed in the course of endoscopic procedures. The present invention's instrument maintains the longitudinal position of its jaws or other manipulation members relative to the body of the instrument regardless of their opening and closing, has greatly improved jaw L/D ratio and column strength, provides greatly improved lateral jaw support and stability during opening and closing, and can include other instrument features in conjunction with a grasping function in order to eliminate or at least minimize the need for multiple or repeated instrument insertions in many procedures.
According to the present invention, an instrument for manipulating an object preferably includes a generally hollow elongated sheath or body, with a selectively operable “handle” or operating assembly generally adjacent one end and one or more jaws or other manipulation members generally adjacent an opposite end. It is important to note that the manipulation member or members are generally fixed, longitudinally, relative to the sheath and is preferably interconnected, directly or indirectly, with the sheath or body. The manipulation member or members are preferably resilient and at least partially deflectable in at least one non-longitudinal direction.
An elongated activation member extends generally longitudinally within the sheath or body for longitudinally movement therein. The activation member, which is preferably a wire or thin cable, can have a round, oval, rectangular, or other cross-sectional shapes that will occur to those skilled in the art. The activation member is interconnected adjacent one of its ends with the handle or operating assembly so as to be selectively moved longitudinally between a retracted position relative to the sheath and an extended position relative to the sheath when the manually operable handle or other operating assembly or mechanism is activated.
A cam member is fixed relative to the activation member, preferably adjacent its opposite end, for corresponding longitudinal movement therewith between retracted and extended positions. The longitudinally moveable cam member engages and forcibly deflects the longitudinally fixed manipulation members or jaws in at least one non-longitudinal direction in response to selective operation of the operating assembly. Thus the cam member forces the jaws or other manipulation members into engagement with the object even though they remain generally fixed relative to the sheath during such deflection, grasping, gripping or holding.
The longitudinally fixed manipulation member assembly can also include two or more thin wire jaws, each optionally having an inwardly or outwardly facing barb or other object-gripping discontinuity, and the jaws can be arranged to be opened or closed upon either extension or retraction of the activation and cam members. The longitudinally fixed manipulation member can alternately be in the form of a snare-type loop, of either a one-piece or multi-piece construction, and can be spread or contracted upon either extension or retraction of the activation and cam members. As a further alternate or optional embodiment, the manipulation member or assembly can have a “basket” type construction or configuration, with two or more arcuate or spiraling members, preferably laterally restrained relative to each other at their proximate or distal ends. When the cam member is extended or retracted, the basket-type members constrict or expand in order to be maneuvered to enclose and grip or grasp the object to be manipulated.
In any of the invention's arrangements, the individual single or multiple jaw or manipulation members can have virtually any cross-sectional shape, such as round or other arcuate shapes, or even rectangular or other polygonal shapes, in order to suit a particular application or to obtain certain desired directional deflection characteristics.
The cam member can be of a disk shape, a rectangular or other polygonal shape, a bead or sphere shape, or even a partially open cup-like shape, with or without recesses therein for receiving barbs or other discontinuities on retracted jaws. Preferably, the cam member has one or more openings extending generally longitudinally through it for slidably receiving a corresponding portion or portions of the manipulation member or members extending therethrough as the extending or retracting cam member forcibly engages the manipulation member or members. The preferred cam members also include outer sleeves that move with them and are long enough to slidably overlap the sheath during extension and retraction in order to minimize the potential for body tissue or other materials being introduced into the hollow sheath.
Optionally, the cam member can also include one or more secondary manipulation members or assemblies interconnected and moveable with the cam member separately and independently of the longitudinally fixed manipulation members. Such “cam-mounted” manipulation members can include a sharpened needle or probe, a knife blade, or a gripping discontinuity for example. Such secondary or supplemental manipulation members can be used in conjunction with the fixed manipulation members to grasp, grip, hold or even cut or sever the object to be manipulated or retrieved.
Also, in an alternate construction, more than one additional wire, cable or other member can be interconnected with the cam member to allow unequal forces to be exerted on different parts of the cam member and cause the cam member to turn or “steer” the sheath or body member along “non-straight-line “paths, such as those typically encountered in medical endoscopic procedures. This arrangement can be used even in instruments not having manipulation jaws, such as when an endoscope is inserted solely for visual observation purposes, for example.
Other objects, advantages and features of the present invention, in addition to those examples mentioned above, will become apparent from the following description and the appended claims, taken in conjunction with the accompanying drawings.